The present invention relates to substituted 2,3-dihydro-6-(hydroxy)pyrimido[2,1-f]purine-4,8(1H, 9H)-diones and tautomers thereof. These compounds are useful as anti-inflammatory agents for treating inflammatory conditions such as arthritis, spondylitis, and tendonitis in mammals. Also these compounds are useful as anti-allergy agents for treating allergy caused diseases.